JPH0519764B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Application of the Invention) The present invention is applied to a head base assembled at a position opposite to the outer peripheral end of a cylinder used in a VTR, etc., so that the tip thereof protrudes from the outer peripheral surface of the cylinder. The present invention relates to a magnetic head height position adjusting device for adjusting the height of a magnetic head, and particularly to a magnetic head height position adjusting device suitable for automation.

(Background of the Invention) As shown in FIG. 5, a magnetic recording cylinder conventionally used in a VTR has two head bases 2 mounted at opposing positions on the outer peripheral end of a cylinder 1, and each of these head bases 2 has a tip end. A magnetic head 3 is assembled so as to protrude outward from the outer peripheral surface of the cylinder 1. Furthermore, in order to correctly reproduce the recording on the magnetic tape, it is necessary to adjust the height ε of the plurality of magnetic heads 3 to within several microns, as shown in FIG. Therefore, conventionally, as described in, for example, Japanese Patent Application Laid-Open No. 57-98131, and as shown in FIG. is fixed to the cylinder 1, and the magnetic head 3 is fixed to the other end.By applying a voltage E between the electrodes of the two piezoelectric elements 6a and 6b, the tip of the magnetic head 3 moves in the direction of the arrow. A device has been invented that allows the displacement to occur. However, since the above method uses piezoelectric elements 6a and 6b, it has the disadvantage that the product price is high.

Therefore, conventionally, as shown in FIGS. 8 and 9, two head bases 2 formed by a screw or the like are fastened to the outer circumferential end of the cylinder 1 with a set screw 7, and the tip of each head base 2 is attached to the outer peripheral end of the cylinder 1. The magnetic head 3 is arranged such that a portion of the magnetic head 3 protrudes from the outer circumferential surface of the cylinder 1.
and form a screw hole 1a in the cylinder 1 at a position corresponding to the back surface of the magnetic head 3,
An adjustment screw 8 is screwed into this screw hole 1a. In this case, the adjustment screw 8 is rotated and moved in the axial direction to adjust the height of the tip of the magnetic head 3 using its upper end. Next, an example of the adjustment method will be explained with reference to FIG. 10. As shown in the figure, the cylinder 1 is fitted onto a rotary table 9 that can be accurately indexed through 180 degrees, with the magnetic head 3 facing downward, and the upper surface is fixed with a chuck 10. In this state, point the tip of the magnetic head 3 horizontally to the TV camera 1.
1, the image is enlarged and displayed on the TV 12, and then the height of the magnetic head 3 is read out by aligning the cursor line 13 provided on the TV 12.
Then, the rotary table 9 is rotated 180 degrees and the height of the other magnetic head 3 is read out in the same manner as above. At this time, if there is a difference between the two magnetic heads 3, the lower adjustment screw 8 is rotated and moved in the axial direction by the adjustment tool 14, and both magnetic heads 3 are adjusted.
A method has been implemented in which the height is adjusted by an amount corresponding to the difference in height. In this method, the product price is lower than that using piezoelectric elements, but on the other hand, there are problems in automating the adjustment work as described below.

(i) That is, the first reason is that the position of the screw hole 1a formed in the cylinder 1 differs slightly depending on the cylinder 1, so it is necessary to align the position of the adjustment tool 14 with the screw hole 1a.

(ii) The second reason is that, as mentioned above, it is necessary to adjust the height ε of the magnetic head 3 to within a few microns, but if this is done using the adjustment screw 8, the amount of deflection of the head base 2 is too small. In this case, the head base 2 may deflect more than necessary due to a slight external force, making adjustment difficult. Furthermore, if the amount of deflection of the head base 2 is too large, the magnetic head 3 will be tilted in an oblique direction, which will change the state of contact between the tip of the magnetic head 3 and the magnetic tape, deteriorating the reproduction function.

(iii) The third reason is that adjustment takes a long time. In other words, even if the adjustment screw 8 is rotated,
Since the position of the tip of the magnetic head 3 does not change until the tip comes into contact with the head base 2,
In the meantime, it's time to play. What is important in adjusting the height of the magnetic head 3 is that after the tip of the adjustment screw 8 comes into contact with the head base 2, it should be rotated slightly at a time. When an operator performs this, he or she must instantly determine the amount of adjustment in the height of the magnetic head 3 by looking at the image on the TV 12, and then adjust the height by turning the adjustment screw 8 little by little based on the result. This increases the mental burden on the operator and makes it difficult to carry out the adjustment, and it is necessary to repeatedly check whether the tip of the adjustment screw 8 has contacted the head base 2 using the TV 12. It will take a lot of time. Furthermore, if you want to do this automatically,
It takes a lot of time to detect the height position of the magnetic head 3.

In order to solve the above problems, a means for detecting the height position of the magnetic head 3 with high precision and high speed is required, but at present, no means suitable for this has been found.

(Objects of the Invention) An object of the present invention is to provide a magnetic head height position adjustment device that solves the above-mentioned conventional problems, enables automation, and enables production of homogeneous and inexpensive regeneration cylinders.

(Summary of the Invention) In order to achieve the above object, the present invention provides an adjustment driver drive mechanism having a compliance mechanism that absorbs variations in the position of the adjustment screw by bending in a direction perpendicular to the axial direction of the adjustment screw, and A head base behavior detection unit that detects when the head has contacted the head base, a screw engagement detection unit that detects that the tip of the adjustment screw has fitted into the hole in the adjustment screw head, and a camera and image processing that measure the position of the magnetic head. It is characterized by having a unit.

(Embodiments of the Invention) Hereinafter, FIGS. 1 to 4 showing embodiments of the present invention will be described.

In FIG. 1, the cylinder 15 is the movable base 16.
is moved up and down by the guide of the slide section 17. axis 1
8 is connected to a pulse motor 19 by a coupling 20, and at the same time has ball bearings 21a, 2.
1b, it is held on the movable base 16.
A hexagonal hole 22 is provided at the bottom of the shaft 18,
A hexagonal ball 27 at the end of the shaft 23 is fitted. The shaft 23 is held by a ball bearing 21c, and the ball bearing 21c is held by the moving base 16 via rubber 21d. Therefore axis 2
3 receives rotational force from the shaft 18, but has flexibility in the axial direction of the adjustment screw 8 and the perpendicular direction. Axis 23
A spline hole 23a is provided in the lower part of the spline shaft 25 of the head of the adjustment driver 24.
They are having sex with each other. The adjustment driver 24 receives a downward force from a spring 26. There is a hexagonal ball 2 at the bottom of the adjustment driver 24.
8 is provided, and a magnetic head height adjustment screw 8 is provided.
Fit into the hexagonal hole 29 on the head of the head and make adjustments.
Further, as shown in FIG. 8, the cylinder 1 is provided with a through hole 1a around the head base 2, which is used for in-plane adjustment of the position of the magnetic head.
In FIG. 1, one end 30a of the lever 30 is bent in a downward right angle direction, and its tip passes through the through hole 1a of the cylinder 1 and contacts the head base 2. The lever 30 swings about a fulcrum 31 and is pressed against the head base 2 by a spring 32. The other end 3 of the lever 30
A detection plate 33 is fixed to 0b, and a non-contact displacement meter 34 measures the width of the gap between the detection plate 33 and the detection plate 33.

With this configuration, when the head base 2 moves downward, the gap width between the detection plate 33 and the non-contact displacement meter 34 changes, so the non-contact displacement meter 34 can detect that the head base 2 has moved downward. Further, the adjusting driver 24 is provided with a convex portion 35, and a reflective photoelectric switch 36 detects when the adjusting driver 24 is pushed by the spring 26, fits into the hexagonal hole 29 of the adjusting screw 8, and descends. Rotary table 9 chucks cylinder 1 at 10
and rotate it 180° for indexing. Further, the position of the tip of the magnetic head 3 is photographed by a TV camera 11.

The control configuration is shown in Figure 2. The microprocessor 37 instructs the motor drive circuit 38 to drive the pulse motor 19 . Also, the image processing circuit 39 is VT
The image from the camera 11 is processed and the height of the magnetic head 3 is sent to the microprocessor 37. The signal from the non-contact displacement meter 34 is processed by a signal processing circuit 40, which will be explained in detail later, and sent to the microprocessor 37 as a signal indicating whether or not the head base 2 has started moving.
sent to. Further, the output of the reflective photoelectric switch 41 which detects whether or not the adjustment driver 24 is fitted into the adjustment screw 8 is also sent to the microprocessor 37. Furthermore, the microprocessor 37 sends a drive command to a motor (not shown) that drives the rotary table 9.

With this configuration, when the cylinder 1 is set on the rotary table 9 by the chuck 10 from the state shown in FIG. 3A, the movable base 16 is lowered. Next, when the pulse motor 19 is continuously rotated, the hexagonal ball 28 of the adjustment driver 24 rotates, and the adjustment screw 8
When the hexagonal hole 29 is in the same phase as the hexagonal hole 29, the adjustment driver 24 is lowered by the force of the spring 26, and the hexagonal ball 28 and the hexagonal hole 29 are fitted together. The state at this time is as shown in Fig. 3 (b). In this state,
The non-contact displacement meter 34 stores the gap width between it and the detection plate 33. As the pulse motor 19 continues to rotate, the adjustment screw 8 comes into contact with the head base 2, and the third
The situation will be as shown in Figure C. Thereafter, the head base 2 begins to descend, and the lever 30 swings accordingly, and the gap width between the non-contact displacement meter 34 and the detection plate 33 becomes smaller. (See FIG. 3D) The state of the output of the non-contact displacement meter 34 during this period is shown in FIG. Second
The signal processing circuit 40 shown in the figure sends a detection signal to the microprocessor 37 when the output of the non-contact displacement meter 34 changes by a predetermined amount from the value stored in the state shown in FIG. Upon receiving the above signal, the microprocessor 37 stops the rotation command of the pulse motor 19, and also controls the rotation of the pulse motor 19 at that time.
memorize the rotational phase of Further, the microprocessor 37 confirms that the adjustment screw 8 is fitted into the hexagonal hole 29 based on the output of the reflective photoelectric switch 41. Furthermore, the microprocessor 37 gives a command to the image processing circuit 39 to measure the height of the magnetic head 3 and read the data. By the above method, one of the magnetic heads 3 is changed by the initial amount, and the coarse adjustment is completed.

Next, after raising the movable base 16, the rotary table 9 is rotated, and the rough adjustment of the other magnetic head 3 is completed.

The microprocessor 37 completes the coarse adjustment 2
The height data of the two magnetic heads 3 are compared, and the amount of rotation of the adjustment screw 8 corresponding to the amount of adjustment for adjusting the height of the higher magnetic head 3 to the height of the other, that is, the lower magnetic head 3, is determined by the screw pitch. Calculate by

By rotating the rotary table 9, the higher magnetic head 3 is positioned below the adjustment unit, and after rotating the pulse motor 19 to the previously memorized rotation phase, the movable base 16 is lowered. After this,
The adjustment screw 8 is rotated by the adjustment driver 24 by the amount of rotation calculated previously, and the fine adjustment is completed after confirming that the magnetic head 3 has moved to the target value using the TV camera 9 and image processing circuit 39. 16 to complete the entire operation.

(Effects of the Invention) According to the present invention, the drawback of the method of adjusting the height of the magnetic head by pressing the adjustment screw against the head base and bending it, which is the problem of the adjustment cost required by a skilled person, is solved by automating the problem. I can,
It is possible to produce homogeneous and inexpensive recycling cylinders.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a magnetic head height position adjustment device showing an embodiment of the present invention, Fig. 2 is its control circuit diagram, Fig. 3 is an explanatory diagram of its operation, and Fig. 4 is an output curve of a non-contact displacement meter. The present invention is applied to FIG.
A plan view of the VTR cylinder, Figure 6 is a cross-sectional front view,
FIG. 7 is a cross-sectional front view showing the main parts of a conventional magnetic head height position adjusting device, FIG. 8 is a plan view showing another conventional magnetic head height position adjusting device, and FIG. 9 is a cross-sectional front view thereof. , FIG. 10 is an explanatory view showing still another conventional magnetic head height position adjustment device. DESCRIPTION OF SYMBOLS 1...Cylinder, 2...Head base, 3...Magnetic head, 6...Vibrator, 7...Set screw, 8...Adjustment screw, 9...Rotary table, 10...Chuck, 11...
TV camera, 12...TV, 13...cursor line, 1
4... Adjustment tool, 15... Cylinder, 16... Moving base, 17... Slide part, 18... Axis, 19... Pulse motor, 20... Coupling, 21a, 21b,
21c...ball bearing, 22...hexagonal hole, 23
... shaft, 24 ... adjustment driver, 25 ... spline shaft, 26 ... spring, 27 ... hexagonal ball, 29
...hexagonal hole, 30...lever, 31...fulcrum, 32...spring, 33...detection plate, 34...non-contact displacement meter,
35... Convex portion, 36... Reflective photoelectric switch, 37...
Microprocessor, 38...Motor drive circuit, 3
9... Image processing circuit, 40... Signal processing circuit.

Claims (1)

[Claims] 1. The tip of the head base, which is fastened to the VTR cylinder with a set screw, is bent by the tip of an adjustment screw that is tightened at a position on the outer periphery of the set screw of the cylinder, and the head base is fixed to the tip of the head base. A magnetic head height position adjustment device that adjusts the height of a magnetic head includes an adjustment driver that rotates the adjustment screw, and a driver drive that is held by a flexible holding part in a direction perpendicular to the adjustment screw. a mechanism, a screw fitting detection section that detects that the tip of the adjustment driver has fitted into the hole of the adjustment screw, a head base behavior detection section that detects that the adjustment screw has contacted the head base, and the magnetic What is claimed is: 1. A magnetic head height position adjusting device comprising: a measuring section for measuring the height position of the head;